Wrist exerciser



FIG. 1 is a top plan view of a wrist exerciser showing my new design, with the bottom plan view being a mirror image thereof;

FIG. 2 is a front elevational view thereof, with the rear elevational view being a mirror image;

FIG. 3 is a right side elevational view thereof; and,

FIG. 4 is a left side elevational view thereof. 

The ornamental design for an wrist exerciser, as shown and described. 